Given the need to reach a more precise evaluation of results in analyses of samples that require the study of the C3 and C4 components of complement as well as the C1 inhibitor, this work had as an objective to verify the feasibility of interval-of-reference transfers as specified by vendor for the afore-mentioned proteins. For this purpose, the sera from adults that turned up for prenuptial tests at the Hospital Laboratory Service was selected. C3 and C4 were measured by means of kinetic nephelometry and the C1 inhibitor by means of radial immunodifussion. To ensure acceptability of the interval-of-reference transfer for C3, C4 and the C1 inhibitor, a decision algorithm was used. The intervals of reference proposed by the manufacturer for C3 and C4 proved to be transferable to the lab, with inclusion percentages of 96 and 100, respectively. On the other hand, the interval of reference proposed by the manufacturer for the C1 inhibitor proved not to be transferable to the lab population.